张北生态退耕遥感监测与评价

Monitoring and Evaluating of Converting Arable Land into Forestland and Grassland through Remote Sensing Technology:A Case Study in Zhangbei County of Hebei Province

张北地处坝上高原农牧交错带,多年来不合理的土地开垦活动,导致本区的土壤沙化程度十分严重,加上自身的自然环境特征,构成了京津地区沙尘暴的主要沙源和运沙通道,鉴于此,我国政府将该地纳为京津风沙源治理和退耕还林工程的重点工程区。本文通过利用高精度的遥感卫星影像对该区前3年的生态退耕情况进行了动态检测,表明目前张北县的生态退耕工作主要是还草,还草的结构主要以人工草地和改良草地为主体;还林的比例相对还草较低,目前的还林结构主要是未成林造林地。指出张北县的生态退耕是具有初步成效的,但是,生态环境的治理是以改善当地经济条件,提高人民的生活水平的为前提的,因此合理利用当地有利的自然地理条件,调整生产结构是生态退耕工作得以顺利实施的保证。

Zhangbei County is located in the interleaving zone between farmland and animal husbandry areas in the north of Hebei province. Because of improper land use, land degradation and desertification in the area have been aggravating and become the major source of sandstorm, which frequently happened in Beijing and Tianjing Area. Therefore, Zhangbei has been identified by national government as the key area for conducting the project of converting arable land into grassland and forestland in order to protect Beijing and Tianjing from scourge of sandstorm. This paper makes an investigation into the land use change in the past three years in the area through based on higher resolution remote sensing images. The results show that converting arable land into grassland is dominant in the process with features of artificial rangeland and improvement of original grassland. The rate of converting arable land into forestland is relatively lower compared with grassland. It is concluded that the effects of converting arable land into grassland and forestland is preliminary in the area and suggested that in the process of ecological restoration, more attention should be given to the improvement of local economy and living standards while properly utilizing land resources and adjusting the structure of agricultural production.